Hi
I am on H1. I donot wish to apply for green card.

Now I know that I can start a C corporation in usa. I would like to start one. And I know I cannot work fulltime on it but can play a managerial role. ( I expect to attend meetings with client twice a month or travel on weekends to ensure business)

My question was,
If I open a Corporation, Can I file my business expenses on my tax return? Can I claim my business expenses?

No, you cannot, not in any practical way, because such expenses would be ITEMIZED deductions subject to a 2% floor, so it is UNLIKELY you will exceed the standard deduction, especially if you are married and filing jointly.

Just have the C corporation reimburse you for your expenses. That IS allowed under U.S. tax law.